Every finding in the evidence table: 382 rows, filterable

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Area All 382 Care, carers and services 140 Medicines 85 Genes (not modifiable) 35 All modifiable factors together 27 Diet and supplements 23 Exercise and activity 21 Sleep, mood and social life 19 Hearing and vision 8 Alcohol, tobacco and cannabis 6 Infection and vaccination 5 Heart and metabolic health 4 Injury, delirium and falls 4 Environment 3 Cognitive activity 2

Question Both Prevention 190 Treatment 192

Direction Any Benefit 144 Harm 105 No effect 38 Mixed 37 No direction reported 58

Design Any meta-analysis 57 randomised trial 44 phase 3 trial 15 systematic review 9 phase 2 trial 10 cohort study 136 phase 1 trial 2 cross-sectional study 31 case-control study 14 modelling study 20 regulatory decision 7 company announcement 1 coverage determination 1 None 35

Showing 4 of 382 rows. One row per study per exposure: a study that tested two different things appears twice, once for each.

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Research and outcomes, 4 rows. Every row links to its source.
Exposure	Question	Direction	Outcome measured	Design	People	Effect size, as the source reported it	Source
Herpes zoster / shingles vaccination Infection and vaccination	Prevention	Benefit	New dementia diagnoses over 5.5 years	cohort study	232,124	-2.0 percentage points (95% CI -3.5 to -0.4) absolute reduction in new dementia diagnoses over 5.5 years	The Lancet Neurology 2026 ✓ Peer-reviewed PMID 41579903
Herpes zoster / shingles vaccination Infection and vaccination	Prevention	Benefit why Regression discontinuity across a birth-date eligibility threshold, which makes confounding by health-seeking behaviour less likely than in a plain cohort comparison. Eligibility did not change uptake of other preventive services or other chronic-disease diagnoses, which is the check that makes the design convincing.	New dementia diagnoses over 7.4 years	cohort study	101,219	"eligibility for HZ vaccination (ie, being born shortly after vs shortly before November 2, 1936) decreased the probability of receiving a new dementia diagnosis during 7.4 years by 1.8 percentage points (95% CI, 0.4-3.3 percentage points; P = .01)"; vaccination uptake rose 16.4 percentage points (95% CI 13.2-19.5) across the threshold	JAMA 2025 ✓ Peer-reviewed PMID 40267506
Herpes zoster / shingles vaccination Infection and vaccination	Prevention	Benefit why Regression discontinuity across the 2 September 1933 eligibility threshold; stronger in women than men.	Probability of a new dementia diagnosis over 7 years	cohort study	not stated	-3.5 percentage points (95% CI 0.6 to 7.1, P = 0.019) in 7-year dementia diagnosis probability; 20.0% relative reduction (95% CI 6.5-33.4)	Nature 2025 ✓ Peer-reviewed PMID 40175543
Other vaccination (influenza, pneumococcal, general) Infection and vaccination	Prevention	Benefit why Pooled observational studies, so open to the confounding the natural-experiment studies were designed to avoid.	Any dementia	meta-analysis	104,031,186	Influenza vaccination RR 0.87 (95% CI 0.77-0.99) for any dementia; pneumococcal vaccination RR 0.64 (95% CI 0.47-0.87) for Alzheimer's disease	Age and Ageing 2025 ✓ Peer-reviewed PMID 41269248

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